1. Field of the Invention
The present invention relates generally to a hydraulic material composition having high strength, and more particularly to such a hydraulic material composition containing a hydraulic material, an ultra-fine particle, a water reducing agent and water.
2. Related Art Statement
It has been known from PCT Patent Application Laid-Open No. 55-500863 and PCT Patent Application Laid-Open No. 57-500645 that a cement composition having fluidity even at a low ratio of water to cement plus ultra-fine particle is obtainable by mixing a cement with an ultra-fine particle composed of silica fume which is a by-product of the process of producing ferrosilicon, and admixing with a water-reducing agent and water, followed by ordinary kneading operation; and that the compressive strength of the solidified mass of such a composition, after being aged in water, is not less than 100 MPa, with a further improvement in compressive strength by the combination of a special aggregate such that the compressive strength increases to 170 to 200 MPa.
However, the aforementioned known composition has a disadvantage that the hydrate contraction thereof is so large as to result in size change due to hydrate contraction or formation of cracking during the production process. On the other hand, it has been generally known that the strength of a solidified product is in close relation with the water/cement ratio so that a product having high strength can be obtained if the water/cement ratio is greatly reduced. The aforementioned known technique is one of the means for reducing the water/cement ratio. However, the fluidity of the composition having a low water/cement ratio significantly varies depending on the specific cement used. There is an ardent demand for the development of a cement composition having improved properties with high strength.